Two years on since Monty Halls, his wife Tam and daughters Isla and Molly first travelled to the Galapagos islands, the family head back to discover why it faces a fight for survival. In the opening episode, Monty experiences the mighty volcanic power that created the islands, mum Tam makes a solo voyage in search of threatened giant manta rays, and Molly, the youngest, has her first snorkelling experience.

Marine biologist Monty Halls and his family are settling into life on the island of Isabela in the Galapagos, where they discover it's not without its challenges. The family find flamingos in an unexpected place and get to know a big fish with a bad reputation. Daughter Isla becomes a young field assistant helping to tag baby Hammerheads, while Tam and Monty mark their wedding anniversary underwater with over 20 endangered sharks.